package server;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.io.SAXReader;
import server.mapper.Context;
import server.mapper.Host;
import server.mapper.Mapper;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.InvocationTargetException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * Minicat的主类
 */
public class Bootstrap {

    /**定义socket监听的端口号*/
    private int port = 8080;

    public int getPort() {
        return port;
    }

    public void setPort(int port) {
        this.port = port;
    }


    /**
     * Minicat启动需要初始化展开的一些操作
     */
    public void start() throws Exception {

        // 加载解析相关的配置，web.xml
//        loadServlet();
        loadServerConfig();

        // 定义一个线程池
        int corePoolSize = 10;
        int maximumPoolSize =50;
        long keepAliveTime = 100L;
        TimeUnit unit = TimeUnit.SECONDS;
        BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<>(50);
        ThreadFactory threadFactory = Executors.defaultThreadFactory();
        RejectedExecutionHandler handler = new ThreadPoolExecutor.AbortPolicy();


        ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(
                corePoolSize,
                maximumPoolSize,
                keepAliveTime,
                unit,
                workQueue,
                threadFactory,
                handler
        );





        /*
            完成Minicat 1.0版本
            需求：浏览器请求http://localhost:8080,返回一个固定的字符串到页面"Hello Minicat!"
         */
        ServerSocket serverSocket = new ServerSocket(port);
        System.out.println("=====>>>Minicat start on port：" + port);

        /*while(true) {
            Socket socket = serverSocket.accept();
            // 有了socket，接收到请求，获取输出流
            OutputStream outputStream = socket.getOutputStream();
            String data = "Hello Minicat!";
            String responseText = HttpProtocolUtil.getHttpHeader200(data.getBytes().length) + data;
            outputStream.write(responseText.getBytes());
            socket.close();
        }*/


        /**
         * 完成Minicat 2.0版本
         * 需求：封装Request和Response对象，返回html静态资源文件
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            response.outputHtml(request.getUrl());
            socket.close();

        }*/


        /**
         * 完成Minicat 3.0版本
         * 需求：可以请求动态资源（Servlet）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            // 静态资源处理
            if(servletMap.get(request.getUrl()) == null) {
                response.outputHtml(request.getUrl());
            }else{
                // 动态资源servlet请求
                HttpServlet httpServlet = servletMap.get(request.getUrl());
                httpServlet.service(request,response);
            }

            socket.close();

        }
*/

        /*
            多线程改造（不使用线程池）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket,servletMap);
            requestProcessor.start();
        }*/



        System.out.println("=========>>>>>>使用线程池进行多线程改造");
        /*
            多线程改造（使用线程池）
         */
        while(true) {

            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket, mapper);
            //requestProcessor.start();
            threadPoolExecutor.execute(requestProcessor);
        }



    }

    private final Mapper mapper = new Mapper();
    private final Map<String,HttpServlet> wrapperAndServletMap = new HashMap<>();

    /**
     * 加载解析web.xml，初始化Servlet
     */
    private Context loadServlet(String path) throws Exception{
//        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream("web.xml");
        //获取部署项目的web.xml文件
        String webPath = path + "/web.xml";
        if (!(new File(webPath).exists())) {
            System.out.println("not found " + webPath);
            return null;
        }
        InputStream resourceAsStream = new FileInputStream(webPath);
        SAXReader saxReader = new SAXReader();

        Document document = saxReader.read(resourceAsStream);
        Element rootElement = document.getRootElement();

        List<Element> selectNodes = rootElement.selectNodes("//servlet");
        for (int i = 0; i < selectNodes.size(); i++)
        {
            Element element = selectNodes.get(i);
            // <servlet-name>lagou</servlet-name>
            Element servletnameElement = (Element) element.selectSingleNode("servlet-name");
            String servletName = servletnameElement.getStringValue();
            // <servlet-class>server.LagouServlet</servlet-class>
            Element servletclassElement = (Element) element.selectSingleNode("servlet-class");
            String servletClass = servletclassElement.getStringValue();


            // 根据servlet-name的值找到url-pattern
            Element servletMapping = (Element) rootElement.selectSingleNode("/web-app/servlet-mapping[servlet-name='" + servletName + "']");
            // /lagou
            String urlPattern = servletMapping.selectSingleNode("url-pattern").getStringValue();

            //            servletMap.put(urlPattern, (HttpServlet) Class.forName(servletClass).newInstance());
            //使用自定义classLoader加载class
            MyClassLoader myClassLoader = new MyClassLoader();
            Class<?> aClass = myClassLoader.loadClass(path, servletClass);
            wrapperAndServletMap.put(path + urlPattern,
                    (HttpServlet) aClass.getDeclaredConstructor().newInstance());
        }
        return new Context(wrapperAndServletMap);
    }

    private void loadServerConfig() {
        InputStream stream = Bootstrap.class.getClassLoader().getResourceAsStream("server.xml");
        SAXReader saxReader = new SAXReader();
        try
        {
            Document document = saxReader.read(stream);
            //获取<Server>
            Element rootElement = document.getRootElement();
            //获取<Service>
            List<Element> serviceElements = rootElement.selectNodes("//Service");
            //host集合
            Map<String, Host> hostMap = new HashMap<>();

            for (Element serviceElement : serviceElements)
            {
                //服务端口号
                Element connectorElement = (Element)serviceElement.selectSingleNode("Connector");
                this.port = Integer.parseInt(connectorElement.attributeValue("port"));

                Element engineElement = (Element)serviceElement.selectSingleNode("Engine");
                //context集合
                Map<String, Context> contextMap = new HashMap<>();

                //获取<Host>
                List<Element> hostElements = engineElement.selectNodes("//Host");
                for (Element hostElement : hostElements)
                {
                    String hostName = hostElement.attributeValue("name");
                    String appBase = hostElement.attributeValue("appBase");
                    File baseFile = new File(appBase);
                    if (baseFile.exists() && baseFile.isDirectory())
                    {
                        File[] files = baseFile.listFiles();
                        for (File file : files)
                        {
                            String contextName = file.getName();
                            Context context = loadServlet(appBase + "/" + contextName);
                            contextMap.put(contextName,context);
                        }
                    }
                    Host host = new Host(contextMap);
                    host.setAppBase(appBase);
                    hostMap.put(hostName + ":" + port, host);
                }
                mapper.setHostMap(hostMap);
            }

        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }


    /**
     * Minicat 的程序启动入口
     * @param args
     */
    public static void main(String[] args) {
        Bootstrap bootstrap = new Bootstrap();
        try {
            // 启动Minicat
            bootstrap.start();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
